Introduction
Relativistic backwave tube is a typical high power microwave device. RBWO has the characteristics of high power, high efficiency and suitable for repetitive frequency operation. At the same time, it also has good frequency tuning ability, [1] relative to C and X bands, the Ku band relativistic backwave tube has a higher frequency and wider bandwidth, more suitable for modern communication. Therefore, it has important application value in the research of Ku band. In 2019, Song Wei et al. realized a backwave tube with a power of 1.06Gw, a frequency of 16.15Ghz and a beam conversion efficiency of 25% under a diode voltage of 620 kV. In this paper, A Ku band relativistic backwave tube with input voltage of 532 kV, transmission current of 3150 A, output power of about 1.38 Gw, operating frequency of about 12.5 Ghz and power efficiency of about 40% is implemented.